Conventional perpendicular magnetic recording (PMR) heads may be unshielded or shielded. Although easier to fabricate and having higher write fields, unshielded heads have a low gradient field. Such a low gradient field results in less sharp transitions and lower signal to noise ratios, which are undesirable. Consequently, shielding is typically provided in conventional PMR heads.
FIG. 1 depicts a portion of a conventional PMR head 10, as viewed from the air-bearing surface (ABS). The conventional PMR head 10 is a shielded head. The conventional PMR head 10 is typically part of a merged head including the PMR head 10 and a read head (not shown) and typically resides on a slider (not shown). For clarity, the conventional PMR head 10 is not drawn to scale.
The conventional PMR head 10 includes a conventional first pole 12, alumina insulating layer 14, alumina underlayer 16 that may be considered part of the alumina insulating layer 14, a conventional PMR pole 18 that typically includes a seed layer (not shown), insulating layer 20, shield gap 26, and top shield 28. Note that in certain other embodiments, the top shield 28 may also act as pole during writing using the conventional PMR head 10. The conventional PMR pole 18 is surrounded by insulating layer 20. Similarly, the top shield 28 is surrounded by another insulating layer (not shown). The conventional PMR pole 18 has sidewalls 22 and 24. In conventional applications, the height of the conventional PMR pole 18 is typically less than approximately three-tenths micrometer. The conventional PMR pole 18 also has a negative angle such that the top of the conventional PMR pole 18 is wider than the bottom of the conventional PMR pole 18. Stated differently, the angle θ of the sidewalls is less than ninety degrees in the conventional PMR pole 18 of FIG. 1. A pole having this height and shape is desirable for use in PMR applications.
Because the conventional PMR head 10 utilizes a top shield 28, the gradient field is improved. In addition, the net magnetic field from the conventional PMR head 10 is at an angle to the perpendicular direction. However, performance of the conventional PMR head 10 may still suffer due to stray side fields. Such stray side fields may cause side erasure of adjacent tracks. In addition, such a wider field profile may give rise to increased magnetic track width. Consequently, the reduced track pitch required for ultrahigh density recording may not be achieved.
FIG. 2 depicts a portion of a conventional PMR head 10′, as viewed from the air-bearing surface (ABS). The conventional PMR head 10′ is a shielded head that includes side shields. The conventional PMR head 10′ is typically part of a merged head including the PMR head 10 and a read head (not shown) and typically resides on a slider (not shown). For clarity, the conventional PMR head 10′ is not drawn to scale.
The conventional PMR head 10′ includes components that are analogous to those in the conventional PMR head 10. Such components are labeled similarly. Thus, the conventional PMR head 10′ includes a conventional first pole 12′, alumina insulating layer 14′, alumina underlayer 16′ that may be considered part of the alumina insulating layer 14′, a conventional PMR pole 18′ that typically includes a seed layer (not shown), shield gap 26′, and shield 28′. The shield 28′ includes top shield 28A and side shield 28B portions. Similarly, the shield gap 26′ includes top gap 26A and side gap 26B portions.
FIG. 3 is a flow chart depicting a conventional method 50 for fabricating the conventional PMR head having a side shield. For simplicity, some steps are omitted. The conventional method 50 is described in the context of the conventional PMR head 10′. The conventional method 50 starts during formation of the PMR pole 18′. The PMR pole 18′ is defined, via step 52. The shield gap 26′ is deposited, via step 54. Thus, both the top gap 26A and the side gap 26B are deposited in step 54. A photoresist mask (not shown) for the shield 28′ is provided, via step 56. The shield 28′ is plated, via step 58. The photoresist mask used for the shield 28′ is then removed, via step 60. Fabrication of the PMR head 10′ is then completed, via step 62. Thus, the PMR head 10′ may be formed.
Although the conventional method 50 may be used to fabricate the conventional PMR head 10′, there are significant drawbacks. For example, the throat height (length perpendicular to the ABS) of the top shield portion 28A and the side shield portion 28B are the same. Similarly, the thicknesses of the top shield gap portion 26A and the side shield gap portions 26B are the same. This may adversely affect performance of the conventional PMR head 10′. In addition, the photolithography carried out for forming the resist masks in step 56 takes place on the pole 18′. As a result, the thickness of the mask may be uneven. Poor edge definition and location may thus result.
Accordingly, what is needed is an improved method for fabricating a PMR head.